Power transmission system



Aug. 14, 1945. w PODESTA POWER TRANSMISSION SYSTEM Original Filed Aug. 2, 1940 2 Sheets-Sheet 1 INVENTOR.

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Aug. 14, 1945.

J. W. PODESTA POWER TRANSMISSION SYSTEM Original Filed Aug. 2, 1940 2 Sheets-Sheet 2 ZL5-C ZED JILSIB Patented Aug. 14, 1945 7 2,382,023 POWER. TRANSMISSION SYSTEM John W. Podes'ta, Ann Arbor, Mich., assignor to American Broach & Machine,0o., Ann Arbor, Mich.', a corporation of Michigan Original application August 2, 1940, Serial No. 349,430, now Patent No. 2,343,420, dated March Divided and this application October 24, 1941, Serial No. 416,315

15 Claims.

The invention relates generally to power transmission systems and more particularly to fluid,

, especially hydraulic, transmission systems.

One object of the invention is to provide a new and improved transmission system for pperating a plurality of motors in a predetermined sequence.

Another object is to provide a new and improved transmission system particularly adapted for use with a broaching machine and including a first hydraulic motor for actuating a main broach slide, a second hydraulic motor for actuating abroach handling mechanism, a third hydraulic motor for indexing a work support, and means causing operation of the motors in a predetermined sequence.

Yet another object is to provide a transmission system having a main and an auxiliary motor, a plurality of pumps supplying fluidto the motors, and means for permitting fluid to be drawn into the auxiliary motor directly from the supply source andwithout going through the pump when the auxiliary motor is driven by the main motor.

Other objects and advantages will become apparent from the following detailed description taken in connection with the accompanying drawings, in which:

Fig. 1 is a diagrammatic view particularly showing the hydraulic circuit of a power transmission system embodying the features of this invention.

Fig. 2 is a diagrammatic view of the electrical :ontrol circuit for the power transmission sys- This application is a division of my pending application Serial .No. 349,430, filed August 2,

1940, issued March 7, 1944 as Patent No. 2,343,420, for Broaching machines. While the power transmission system herein claimed is readily applicable to a variety of machines and uses, it is par .ticularly applicable to a broaching machine. as

disclosed in my above mentioned copending ap-' plication. Accordingly, the power transmission system will, for purposes of disclosure, herein also be described as adapted for a broaching-machine, but it is not intended that the invention is to be means I I0, PH and PI, respectively, the fluid supplied being under the control of suitable valve means. These valve means in turn are under the control of an electrical governing system.

Such a power transmission system is readily adaptable to a broaching machine, for example,

to one of the internal, pull down type disclosed in my above mentioned application. Such a machine has an upright column on which is vertically reciprocable a main broach actuating slide ll. Disposed in front of the column about midway thereof is a work supporting means including a rotary, indexable work supporting table 2|.

The table is loaded by an operator standing in front of the machine'and is operable to carry the work from the loading position first to a broaching position, where it is acted upon by the broaching tool, and thereafter carries the work to a discharge position where the work is automatically unloaded. Such a machine-also has broach handling mechanism, generally designated 22, which functions to support the broaching tool above the work support during the presentation of anew work blank and to initiate passage of thetool through the work blank.

In the adaptation of the power transmission system to such a machine, the main motor 24 actuates the main slide H, the auxiliary motor 55 'actuates the broach handling mechanism, and the third motor is utilized to index the work table 2 I. The control means of the system renders it, and hence the machine, automatic in operation.

. More particularly the system drives the machine limited thereby. On the contrary, it is intended to cover all modifications, alternative constructions, and adaptations fallin within the spirit and scope of the invention as defined in the appended claims.

The power transmission system comprises generally a main hydraulic motor 24, an auxiliary hydraulic motor 55, and a. third hydraulic motor 8|. Fluid is supplied to these motors by pump in the following manner: The machine is initially started and finally stopped manually by the operator, all other cycles of operation automatically repeating. In a cycle of operation, the broach handling mechanism first moves downwardly to pass the broaching tool through the work and into engagement with the main broach actuating slide, whereupon the main slide moves downward- 1} to pull the broach through the work. During the broaching operation,.the operator loads a new work. piece onto the table 2| and, upon completion of the broaching operation and while the main slide remains down, the table 2| is automatically indexed through to carry the finishedwork piece to discharge position and also i normal position, the table 2| is again indexed, thereby presenting new work pieces to broaching position and the machine is ready for the cycle to be repeated.

an outer, larger and concentric pipe 28 whichforms an annular passage 29 by which fluid is supplied through apertures 38 located near the piston 26 to the rod end of the cylinder. At its lower end, the slide I1 is formed with an integral, forwardly projecting bracket 3| carrying a broach pull head, generally designated 32. This pull head is more fully disclosed and described in my above mentioned application and is composed of *a plurality of individual heads of the general character disclosed and claimed in the Lapointe Patent No. 2,027,486. Suffice it to say, therefore, that the head 32 is adapted releasably to receive one end of one or more breaching tools 34.

Likewise the hydraulicmotor, generally desig- 1 nated 55, is of the reciprocatory type and comprises a cylinder 56 and a piston 51. This motor, as above stated, actuates the broach handling mechanism which includes an auxiliary slide 45 reciprocable in guideways formed in the end of the slide l'l opposite the bracket 3|. This slide in turn carries a plurality of individual tool receiving heads 46 the construction of which is more particularly disclosed and claimed in my above mentioned application. Suffice it to say, therefore, that the heads 46 hold the tools inserted therein releasably so that at the appropriate time they may be withdrawn by the main slide I! through the head 32. As here shown, the piston 51 forms the stationary element of the motor and to that end is through the medium of a double piston rod anchored to the upright column at the bottom thereof. An internal, hollow piston rod 58 extends through the piston 51 so as to upply fluid to the head end of the cylinder, while an outer, larger and concentric rod 59 forms an annular passage 68 for conducting fluid through port 6| to the rod end of the cylinder. The upper end of the cylinder 56' is connected by an adjustable rod 62 to the slide 45 of the broach handling mechanism. The motor-55 is disposed immediately in front of the mainslide I1 and passes freely through a bore provided in the bracket 3| for that purpose. The slide 45 of the broach handling mechanism always remains above-the table 2|, while the head 32 always remains below the table 2|. A

.may be designed to accommodate the particular work blanks to be broached. The work supports are by suitable means, disclosed in my original application above mentioned, yieldably retained in work supporting position, but are tiltable by means later described to a position from which the work blanks will be discharged radially out-' wardly and downwardly.

In order that the motor 8| may serve to drive This means includes a Geneva mechanism com-' prising a disk 16 rigid with the bottom of the table 2| and provided with the usual four radial and spaced grooves 11. Adapted to engage in the grooves 11 is a follower 18 carried by a quadrant 19 rigid on a shaft '88 journaled in the bed of the machine. The shaft 88 is driven from the rotary hydraulic motor 8| through a worm 82 on a shaft coupled to the motor shaft 83 and a worm wheel 84 fixed on the shaft 88. It is to be understood, of course, that the radius of the quadrant and of the disk 16, as well as the spacing of the shafts 61 and 80, is such that upon rotation of the quadrant 19 the follower 18 will enter one of the grooves 11 and operate therein to rotate the table through 90 and will thereafter leave the groove and, during the remainder of the revolution of the quadrant 19, return to initial starting position to enter the end of the groove 11 spaced 90 from the groove previously entered. In visualizing this operation and structure, it should be borne in mind that I9 is a quadrant witha radius approximately equal to that of grooves 11 andthat, as shown in Fig. 1, it faces almost directly out of the sheet so that this radius is not apparent.

Means is also provided for positively locking the table 2| in its various positions. To that end, the disk 16 is provided with four sockets 85, while reciprocably mounted in the bed of the machine is a locking plunger 86, for cooperative engagement with the sockets 85. The plunger 86 is urged to locking engagement by a compression spring 81 and is disengaged from a socket 85 and held in disengaged position during the indexing of the' table 2| through the medium of a cam follower 88, carried by the plunger, and an arcuate cam 89 carried on the underneath surface of the quadrant 1!]. The cam is of a length and so positioned relative to the follower i8 that the plunger is shaft has secured non-rotatably thereto alever 94 (Fig. 1) carrying a follower 95 adapted to be .the shaft'is rotated in the proper direction to tilt the work support 10 for the purpose of discharging the work blanks. Also non-rotatably fixed on the shaft 93 is a lever H which is engaged at its free end by a tension spring I82, the other end of which is anchored in the frame of the maprises. a main pumping unit H composed of a variable delivery piston type main pump, a charging or make-up pump, and a hydraulically shifted fluid flow reversing means all housed in the same casing. Such a pumping unit is disclosed and claimed in the Gunnar A. Wahlmark U. S. Letters Patent No. 2,280,875, dated April 28, 1942. The pumping unit has a first port connected by a conduit III to the inner piston rod 21 of the hydraulic motor 24, a second port connected by a conduit H2 to the annular passage 29 formed by the outer piston rod 28, an intake port for the make-up pump connected by a conduit II3 to a reservoir or tank T to draw from the tank fluid to compensate for the difierence in volume of opposite ends of the cylinder 25, and a discharge port connected to the tank T by a conduit H3.

This latter discharge port serves in well known manner to permit return to the tank of the excess fluid supplied by the make-up pump and the excess resulting from the difierence in the volume of opposite ends of the cylinder 25.

The pumping unit H0 is adapted to be driven continuously in one direction by suitable motor means (not shown herein) and reversal of fluid discharge from the pumping unit is efiected by shift of the fluid flow reversing means, while variation in displacement is effected by adjustment I of the stroke ofthe piston under the control of a hydraulic motor I I5. The motor I I5 and the fluid flow reversing means are in turn controlled by a pair of pilot valves II 6 and I I! which are spring urged to a normal position and are shifted to actuated position by the energization of solenoid coils MD and MU, respectively. The valves H6 and I II are connected in a pilot circuit which includes a conduit H8 in which the valve H6 is interposed and a conduit H9 in which the valve II'I'is interposed. These conduits connect at one end to the opposite ends of the reversing means a reversing valve I29. The reversing valve I29 is in turn connected by a conduit I to the inner piston rod 58 and by a. conduit I3I to the annular passage 60 -formed by the outer piston rod 59 of the motor 55. Relief valves I32 and I33, respectively, are connected to the conduits I and I3I to permit discharge to the tank under abnormal conditions, while also connectedto the conduit I30 and communicating with the tank is a conduit I34 which includes a check valve I arranged to prevent flow to the tank but to. permit fluid to be drawn into thehead end of the cylinder 56 to make up the deficiency during the time that'the slide is raised by the main slide at a rate greater than the rate of fluid supply to the .head end of the cylinder by the pump PH. A return conduit I36 leads from the valve and at the other end join to form a common con duit I20 leading to the pressure source as will presently become apparent. Connected at one end to one end of the governing motor H5 and joining at the other end with the conduit H8 intermediate the pumping unit and the valve I I6, is a conduit I2I, while a conduit I22 is similarly connected to the conduit H9 andto the opposite end of the motor I I5 to supply fluid to one end or the other of the motor H5 in accordance with the shift of the valves II 6 and II I. Exhaust fluid is returned to the tank through conduits I23 and I24. A suitable back pressure check valve I25 is interposed in the conduit H2 to permit free flow of the fluid when supplied to the rod end of the cylinder 25 for the purpose of effectinga return stroke, but which maintains the fluid discharged from the rod end of the cylinder under a predetermined back pressure to assure a uniform movement of the slide during a broaching stroke.

Fluid for actuating the motor 55 of the broach handling mechanism and the indexing motor IN is supplied, respectively, by pumps PH and PI of a double pump unit I26 which also is continuously driven by the electric motor driving pump unit H0. The pump PH has an intake port connected with the tankT through a conduit I21 and a discharge port connected by a conduit I28 to to the tank T. I

Shift of the reversing valve I29 is effected hydraulically under the control of pilot valves I31 and I ,38, respectively shiftable from normal position by energization of solenoid coils SDand SU. Energization of the SD coil and resultant shift of the valve I31 causes operating fluid to be supplied to the rod end of the cylinder 56 to efiect a downward movement of the slide 45.

Conversely, energization of the SU coil with its from the valve I44 is a conduit I45 connected to the intake port ofthe motor 8| and a conduit I46 leading to the tank T. Fluid is exhausted from the motor 8| and returned to the tank through a conduit II" which has interposed therein a back pressure check valve I48. The conduit I43 has interposed therein a back pressure valve I49 to maintain a predetermined pressure for the pilot circuit when the valve I44 permits discharge to the tank T, and has connected thereto a relief valve I 50 permitting discharge to the tank under abnormal conditions.

Shift of the start and stop valve I44 is under the control of a pilot, valve I5I, similar to the valves I31 and I38, and is in turn governed by a solenoid coil I. Pilot fluid for governing the positio'n of the valve I44 is supplied to the pilot valve I 5I through a conduit I52 communicating with theconduit I43 in advance of the back pressure valve I49. A branchconduit I52 connects to the conduit I20 to supply fluid to the remainder of the pilot circuit. Energization of the solenoid coil I functions to shift the valve I44 in a direction to permit the pump PI to supply fluid to the indexing. motor 8I. The valves I31, I38 and I5I are, of course, provided with conduits leading to the tank T permitting the exhaust of fluid from the valvesl29 and I 44.

The various solenoid coils just mentioned are connected in an electrical control circuit see Fig. 2) .which also includes a plurality of automatically actuated or manually actuated switches and relays functioning to energize the solenoid coils at proper times so as to effect automatic opera tion' of the broaching machine once the same has been; started'by manual manipulation of a starting switch. The automatically actuated posed of one or more switches.

ried on the slide 45.

switches include limit switch devices ILS, ZLS, 3L8, 4L8, LS, GLS, 'ILS, BLS and SLS (see Fig. 1). Each of these limit switch devices has a normal position to which it tends to return, a tripped position in which it remains only so long as physically held, and each i adapted to control one or more circuits and to that end is com- Of these limit switch devices, ZLS, 3L8, and 915 are adapted to be tripped at various times by a dog DI car- The device 215 has three switches ZLS-A, 2LS-B and 2LS-C (see Fig. 2) of which the 2LS-A and 2LSB switches are normally open and the ZLS-C switch is normally closed. The 3L5 device has but a single switch 3LSA which is normally open, and likewise the SL5 device has but a single switch 9LS-A which is normally closed.

Switch devices 6L8, 'ILS and'4LS are adapted to be actuated by dogs D2,- D3 and D4, respectively, mounted on and carried by the main slide I1. Both the devices ELS and ILS have but a single switch 6LS-,A and 'ILSA, respectively, the first of which is normally closed and the second normally open. The ILS device has three switches 4LSA, 4LS-B and 41S-C, of which 4LS-A and ILS-B are normally open and 4LSC is normally closed. The ILS device is governed by the table locking plunger 86 which for that purpose has depending therefrom a rod I55 which serves to trip the device when the plunger is withdrawn to free the table 2|. The ILS device has two switches, ITS-A which i normally open, and ILS-B which is normally closed. Also related in its control to the indexable work table 2| is the switch device 5L8 having a single switch 5LS-A which is normally closed. This switch device is governed by an arm I56 which rotates with the shaft 80 of the worm wheel 84 and the quadrant I9. The remaining limit switch device 8L8 also has but a single switch 8LSA which is n'brmally open. This device is controlled by the mechanism for effecting tilt of the work supporting plates III to work discharge position and is held tripped when the mechanism is in normal position. To effect such control over the switch device 8LS, there is pivotally connected to the arm I III a depending rod I51 which terminates above the actuating arm of the switch device 8LS.

The electrical control also includes a plurality of relays IR, 2R, 3R, 4R and 5R. Of these the relays IR, 2R and 3R are latched relays each having two coils designated in the circuit diagram (Fig. 2) by the reference character applied to the relay plus and L and a U, respectively. Each relay has two positions to which it is shifted by temporary energization of the appropriate coil and in which it is held by mechanical detent means until the other coil is energized. The redescription, the 2R-X switch is opened upon energization of the L coils, while the RY Switc is opened upon energization of the U coil. This is for the purpose of assuring temporary energization of the coils only, the latched character of they relays and particularly the cooperation 'of the detent means making this arrangement possible.

The relays 4R and 5R. are not latched relays, but are ordinary relays having but a single coil, designated in Fig. 2 as IR and 5R, respectively. The relay 4R has four switches 4R-A, IIRB,

lRr-D and dR-E, which are all normally open when the relay is deenergized and which are closed upon energization of the rela coil 4R.

Relay 5R has three switches 5Rr-A, 5Rr-B and 5Rr-C which also are open when the relay is in normal condition, namely, with the relay coil 5R deenergized, and which close upon energization of the coil 5R. It will become apparent as the description of the circuit and of the operation of the machine proceeds that the relays IR and SR govern the indexing of the table, that the relay 2R controls the pilot valves governing the direction of fluid flow to the motor of the broach handling mechanism, that the relay 3R controls the pilot valves governing the direction of fluid flow to the main slide motor, while relay AB is a monitor or master relay.

The various solenoid and .relay coils and the various limit and relay switches are connected in a control circuit shown diagrammatically in Fig. 2, which comprises a transformer Tr having a primary winding P connected to a high voltage source, and a secondary S having its ends connected to lead wires LI and L2. Connected between' the wires LI and L2, in a plurality of minor or subcircuits, are the various switches and coils. A first such subcircuit ScI includes in series the relay coil 4R, a normally open, manually actuable starting switch M and a normally closed, manually actuable" stop switch SS. Connected around the start switch M in a shunt circuit I is the switch dR-A which forms a holding circuit for the relay coil 4R. Connected inseries to form a are connected in series between the line wires LI and L2 to form a subcircuit 36:3, and a fourth lay IR has five switches IR-A, IRB, IRC,

IRC and IRX are" the relays the 2RX switch is in series with the L coil, while the 2R-Y switch is in series with the U coil, and,-as will be seen from the above.

subcircuit S04 is formed by the series connection of the switches ILSA, IRY and the IR-U coil. .A fifth subcircuit Sc5includes in'series connection the coil IRL and .switches IR-X and 1LS A and includes a shunt circuit I connected around the switch IR,X and the coil IR--L having in series the switches 3R,A and 2RX and the coil 2R-L. A sixth subcircuit S06 includes in series the switches ILS-B, 2LS--B. IR-B and 2RY and the coil 2R,U. Connected about the coil ZR-U and all the switches save I LS-B is a shunt circuit I66 which includes in series the switches 4R-D and 4R--E. Connected between these last named switches in four parallel circuits are the solenoid coils SD. SU, MU and MD for the valves I31, I38, III and the switches lLS-B,

2,389,023 I the broaches are received in the pull head, the

H6, respectively. In series with the coil SD are switches QLS-A, 2R-B and IR-C. In series with the coil SU are the switches 218-0, 2R-D and Ili -E. In series with the coil MU are the switches 6LSA, 3R--B and lR-C. In series with the coil MD are the switches lIS-C, lR-D and'3R-E. A seventh subcircuit Sc! is formed by the series connection between the line wires LI and L2 of the switches IISA, IR-A and SR-X and the coil iR-L, while an eighth and,

final subcircuit $08 includes in series connection the switches 4LSB, lR-C and iR-Y and the coil "3R-U.

In order :better to understand the sequence of movements or operations of the various motors, as well as the functions of the various switch devices, valves and so forth, the operation of the power transmission system will be described briefly in terms of the operation of the broaching machine. For that purpose, let it be assumed that the machine is idle in its normal starting position, that is, with the slide 45 of the broach handling mechanism and the main broach actuating slide both in their uppermost positions, and with the table 2| disposed with one work support in the broaching position, while the other work support is at the front of the machine where it can be loaded by the attendant. It is to be assumed further that unfinished work blanks are mounted in the work support which is in broaching position. Under these conditions the limit switch device 218 will be tripped by the dog DI on the slide 45, the device GLS will be tripped by the dog =D2 on the main slide, switch device 518 will be tripped by the arm I56, and switch device 8LS will be tripped by the rod I 51 of the work support tilting mechanism. The other switch devices will be in their normal position, relays 4R and SR will be deenergired and all their switches open, all of the solenoid coils of the pilot valves W111 be deenergized, while the coils of the relays IR, Zn and 3R will also be deenergized. In short, the switches will assume the positions shown in Fig. 2. To start operation, the attendant first starts the electric motor, which drives the pump and then momentarily presses the start button M, thereby completing the subcircuit Sci to enersize the 4R relay coil. Such energization of the coil 4R closes all of the switches of the 4R relay, among other things, to establish a holding circuit for the relay through the closure of the 4R-A switch and to complete the shunt circuit I, through that branch which includes the coil SD in part governing operation of the slide 45, through the closure of the switches 4R-D and lR-E. As a: consequence, the slide II is started on its forward or, in this instance, downward stroke, since a circuit is now completed through lR-D, SIS-A, 2R-B, 2R-C and lRP-E to energize the coil SD of the valve I31. Such shflt energization of the coil SD, causes the reversing lR-C is open;

of the valve "1, due to valve I29 to shift so that fluid is supplied to the rodend of the motor ward movement of the'slide 4!, the switch de- 55. With the initial foralone and relative to the slide ll carrying itsbroaches through the work pieces and into the pull head 32. {it the time that the lower ends oi tion of the 3R-L coil shifts the relay to open its 3R-X switch deenergizing the 3R-L coil, closing its 3R-Y switch preparatory to a subsequent energization of the 3R-U coil, opening. its SR-A, 3R-B and 3R-C switches and, above all, closing its 3Rr-D and 3RE switches. Closure of these latter switches completes a circuit energizing the coil MD of the pilot valve I I6, which results in the pumping unit llil supplyin fluid to the head end of the cylinder 25 to initiate the .broaching stroke of the main broach actuating slide. With the initial movement of the main broach actuating slide, the limit switch device GLS is permitted to return to normal positionresulting in aclosure of its switch BLS-A. Such closure, however, is ineffective to energize the coil MU because of the .previous opening of the switches 3R-B and 3R-C.

The slide 45 and the main'slide now continue downwardly in unison through the broaching stroke until the dog DI trips the limit switch device SIS, opening its switch 9LS.A and thereby deenergizing the coil SD. With such deenergization of the coil SD, the valve |3l is returned to normal position and the reversing valve I29 is returned to neutral position stopping movement of the slide 45-. The main' slide, however, continues downwardly to complete the broaching operation. and to withdraw the broach from the broach handling heads of the slide 45 and through the work supports on the table 2|. During the broachinsstroke of the main slide, the dog D3 temporarily trips the switch device 1L8, temporarily to close its switch 'lLS-A. Such closure of the switch ILS-A completes the subcircuit S05 to energize the relay coil lPv-L, resulting in the opening of the relay switches lR,-B, IR-C and IR X and closing of the switches lR-A and lR-Y. No immediate change takes place as a result, but the opening or closing of the certain switches serves to condition the circuits in which they are included for future operation, as willstroke of the main slide. Closure of the switch LS-B accomplishes nothing because switch However, closure of switch lbs-A completes a circuit to the relay coil 5R through the switches 8LS-A, LS-4i, lR-A and lR-B .which are now all closed. Energization of the coil 5R results-in a closure of all of the relay switches IR-A, SR-B and iR-C, the closure of SR-B and- IR-C resulting in the completion of the subcircuit S03 to energize the coil I. With the energization of the I coil, the pilot valve Iii is shifted in turn to effect a shift of the valve I, permitting flow of operating fluid to the indexing motor 8|, resulting in commencement of the indexing operation.

With the initial rotationof the shaft and the quadrant I9 non-rotatably fixed therewith, the arm I" releases the switch device BIS to permit its return to normal, resulting in a closure of its switch lLS-A. Closureoi this switch establishes a circuit for the coil R which is independent of the switch IR-A which will presently be opened to place sole control over the indexing motor 8| in the switch device 5LS. Also, with the initial rotation of the shaft 80 and prior to'entry of the follower 18 into a groove 11, the cam 89 on the quadrant I9 engages the cam follower 88 to withdraw the locking plunger 85 and at the same time through the rod I55 trip the switch device ILS. Tripping of the switch devic ILS opens its switch ILSB, rendering the MU and MD coils incapable of 'energization and closes ILSA which completes the subcircuit Sc4 to energize the coil IRU. Energization of the IR-U coil of the relay IR opens the relay switches IR-Y and IR--A, opening of the latter placing the switch 5LS-A in full control of the indexing motor, as above stated. Energization of the IR-U coil also results in a closure of switches IR-X and IR-B, which closure has no effect save to condition circuits for future use, and closure of switch IR-C completes the subcircuit S08 energizing coil 3R--;U of the relay 3R. Energization of the 3R-U coil in turn efiects closure of the relay switches 3R-A, 3R-B, 3RC and 3R-X. However, closure of switches 3R-B and 3R-C does not initiate upward movement of themain slide because ILSB is still open. The switches 3R-D, 3R--E and 3Rr-Y are also opened as a result of energization of 3RU.

When the indexing of the table 2| is complete, that is, when it has been rotated through 90 so as to carry the work blanks from broaching position to an unloading position, the cam 89 disengages from the follower 88 permitting the plunger 85 to engage with a socket in the table 2| to lock the same and, incidental thereto, the switch device ILS is returned to normal position. With such return to normal position, its switch ILSA is opened and its switch ILSB is closed. Opening of the switch ILSA has no efiect, but closure of the switch ILSB results in completion of the handling slide until the upper ends of the broaches are restored to the heads in the slide 45, which takes place. about the same time that the key K on the main slide engages key K on the slide 45. Prior to such engagement of the key K with the slide 45, the dog D3 momentarily trips the switch device 'ILS, temporarily closing its switch ILSA. Such temporary closure of the switch ILSA completes circuits energizing both the IR-L and the 2RL coils Energization of the IR-L coil of the relay IR causes its switches IR-B, IRC and IR-X to be opened and its switches IR-A and IR-Y to be closed, but no immediate change is effected. Energization of 2R-L opens the relay switches IR-A, ZR-B, ZR-C and 2R-'-X and closes the relay switches 2R-D, 2R-E and 2R--Y. Closure of the switches 2R--D and 2RE completes a circuit to the coil SU of the pilot valve I38, thereby effecting a shift in the reversing valve I29 in such direction that fluid is supplied to the head end of the cylinder 56. The broach handling slide .45 and the main slide now move through their return stroke in unison.

With the initial return movement of the slide 45, the switch device 9L8 is, of course, released and permitted to return to normal, resulting in a closure of its switch ills-A. Closure of this switch, however, does not energize the coil SD since the switches 2R-B and ZR-C have previously been opened as a result of the energization circuit including the coil MU, which circuit had been previously conditioned by closure of the switche 3R-B and 3R--C. Return movement of the main slide is now initiated, since the energization of the coil MU causes the pumping unit IIII under the control of the pilot valve III to supply fluid to the rod end of the cylinder 25.

Some time after the initiation of the return stroke of the main slide, the shaft 80 completes its revolution, causing the arm I56 to trip device 5LS, thereby, opening switch 5LS-A and arrestin operation of the indexing motor 8 I.

With the initial return movement of the main slide, the switch device 4LS is permitted to return to normal, resulting in-the opening of its switches 4LS-A and 4LS-B, and .closing of its switch 4LSC. 'Nothing transpires immediately from this change, not even from the closure of 4LSC, for the switches 3R--D and 3R-E "are open. During the return movement of the main slide, the cam 95 carried thereon engages the follower 95 to rock shaft 93 and the lever 99 normally coupled thereto. Such rocking of the shaft 93 tilts the work support I0 which carries the finished work pieces causing the same to be discharged. At the same time, rocking of the shaft 93 withdraws the rod I51 to permit the switch device 8LS to open its switch 8LSA which is its normal condition. The switch is, of course, again closed immediately upon return of the work support to its normal horizontal position.

During the return stroke, the main slide initially moves alone and relative to the broach of the'2RL coil. During'the return movement of the slide 45, the dog DI also temporarily trips the switch device 313, but, like the switch 9LS, is inefiective because the switch 2R-A is open at such time. The two slides continue in unison until the dog D2 trips the witch device BLS, effecting an opening of the switch 5LS-A. Because of the opening of the switch 5LS- A, the circuit, to the coil MU is broken and, with the deenergization of the coil, the pumping unit IIll discontinues supplying operating fluid whereby the main slide comes to rest in its uppermost normal starting position. The slide 45 now continues in its return movement independently of the main slide and until its dog DI trips the switch device ZLS.

With the tripping of the device ZLS, its switch 2LSC is opened to deenergize the coil SU, resulting in a return of the reversing valve I29 to neutral position and cessation of flow of fluid to the motor 55 of the broach handlingmecham'sm bringing the slide 45 to a stop in its uppermost normal starting position. Tripping of the device 2LS closes its switches ZLS-B and 2LS-A, closure of the latter serving to complete a circuit energizing'the coil 5R. This results in closure of all of the 5R relay switches," namely 5RA, 5R--B and 5R-C to again partially establish a holding circuit for the relay SR and to complete the subcircuit Sc3 to energize the coil I. With the energization'of the coil I; the indexing motor BI is started, as previously described, and with the initial operation of the motor the switch device 5LS is permitted to return to normal, while the switch device ILS is tripped. Return of the switch device 5LS to normal closes its switch 5LS-A to complete the holding circuit for the relay coil 5R. Tripping of the switch device ILS opens ILS-.-B again to render all of the solenoid coils on the pilot' valves incapable of energization and closes the rotation of the same through 90 which has now again placed one of the work supports in the broaching position, while the other is'at the front of the machine ready to be loaded by the attendant, the table is locked and the switch device ILS returned to normal. Such return to normal opens its switch ILSA and closes its switch lLS-B to complete the subcircuit S06 and energize the coil 2R-U. Such energization of the coil opens the relay switches 2R--D and 2R-E and closes the relay switches ZR-A, lRr-B and 2R-C. Closure of' the latter two completes the circuit to the coil SD of the pilot valve I31, initiating a new cycle of operation of the broaching machine.

I claim as my invention:

1. In a hydraulic power transmission system, the combination of a main fluid motor, an auxiliary fluid motor, said motors being movable through forward and reverse strokes in the same direction, a first hydraulic circuit including said main motor and a pump means forming a source of fluid under pressure for operating said .main motor, a second hydraulic circuit independent of said first circuit including said auxiliary motor and a pump for supplying fluid thereto at a constant rate, a reservoir for the fluid, means for controlling the supply of fluid to said motors, means forming a separable mechanical connection between said main and auxiliary motors, governing means for operating the control means to cause said main and auxiliary motors to move through a cycle of non-simultaneous but partially concurrent forward and reverse strokes, the main motor driving the auxiliary motor by said mechanical connection during the concurrent portion of said reverse stroke at a rate in excess of that at which it is driven by fluid supplied there to, a conduit connecting the reservoir and the side of said second circuit constituting the supply side during the reverse stroke ofsaid auxiliary motor. and check valve means in said conduit permitting fluid to be drawn into said auxiliary motor directly from said reservoir.

2. In a hydraulic power 'transmission system,

,the combination of a main fluid motor, an auxiliary fluid motor, said motors being movable through forward and reverse strokes in the same direction, pump means forming a source of fluid under pressure for operating said motors, a reservoir for the fluid, means for controlling the supply of fluid to said motors, means forming a separable mechanical connection between said main and auxiliary motors, governin means for operating the control means to cause said main and auxiliary motors to move through a cycle of nonsimultaneous but partially concurrent forward and reverse strokes, the main motor driving the auxiliary motor by said mechanical connection during the concurrent portion of said reverse stroke, and check valve means permitting flow directly from the reservoir to said auxiliary motor during the concurrent portion of the reverse stroke of said main and auxiliary motors.

3. In a hydraulic power transmission system, the combination of a main fluid motor, an auxiliary fluid motor, said motors being movable through forward and reverse strokes in the same direction, pump means forming a source of fluid under pressure for operating said motors, hydraulically actuated means controlling the sup ply oi. fluid to said motors, means forming a separable mechanical connection between said main and auxiliary motors, and governing means for lid hydraulically actuated control means including a fluid control circuit operating said control means to cause said main and auxiliary motors to move through a cycle of non-simultaneous but partially concurrent forward and. reverse strokes, the main motor operating the auxiliary motor by said mechanical connection during the concurrent portion of said reverse strokes.

4. In a hydraulic power transmission system,

the combination of a main fluid motor, an auxiliary fluid motor, said motors being movable through forward and reverse strokes in the same direction, a first and a second pump means forming a source of fluid under pressure for operating said main and said auxiliary motors respectively, a hydraulically actuated fluid flow reversing means determining the direction of fluid flow between said first pump means and said main motor, a hydraulically actuated fluid flow reversing means determining the direction of fluid flow between said second pump means and said auxiliary motor, means forming a separable mechanical connection between said main and said auxiliary motors, and governing means for said reversing means including a fluid control circuit and a pair of electrically operated valves for each-reversing means governing the supply of control fluid to said reversing means.

5. In a, hydraulic power transmission system, the combination of a main fluid motor, an auxiliary fluid motor, said motors being movable through forward and reverse strokes in the same direction, a first hydraulic circuit including said main motor and a pump means forming a source oi fluid under pressure for operating said main motor, a hydraulically actuated fluid flow reversing means determining the direction of fluid flow between the pump and said. main motor, a second hydraulic circuit independent of said first circuit including said auxiliary motor, a pump means forming a source of fluid under pressure for operating said auxiliary motor and a hydraulically actuated fluid flow reversing means. in-- terposed between the pump and motor, means forming a separable mechanical connection between said main and auxiliary motors, and governing means including a third hydraulic circuit, constituting a control circuit for said fluid flow reversing means, goveming said valves to cause said main and auxiliary motors to movethrough a cycle of forward and reverse strokes with a portion of the strokes in eachdirection being concurrent and with said motors connected through said separable mechanical connection.

6. In a hydraulic power transmission system, the combination of a main fluid motor, an auxiliary fluid motor, said motors being movable through forward and reverse strokes in the same 1 direction} a first hydraulic circuit including said main motor and a pump means forming a source of fluid under pressure for operating said main motor, a hydraulically actuated fluid flow reversing means determining the direction of fluid flow between the pump and said main motor, a

- second hydraulic circuit independent of saidflrst circuit including said auxiliary motor, a pump means forming a source oi fluid under pressure for operatinglsaid auxiliary motor and a hydraulically actuated fluid flow reversing means interposed between the pump and motor, means forming a separable mechanical connection between said main and auxiliary motors, and governing means including a. third'hydraulic circuit, constituting a control circuit for said reversing means, electrically actuated valves controlling the fluid in said third circuit, and an electrical circuit controlling said electrical valves to cause cuit including said main motor and a pump means forming a source of fluid under pressure for operating said main motor, a hydraulically actuated fluid flow reversing means determining the direction of fluid flow between the pump and said main motor, a second hydraulic circuit independent of said first circuit including said auxiliary motor, a pump means forming a source of fluid under pressure for operating said auxiliary motor and a hydraulically actuated reversing valve interposed between the pump and motor, means forming a separable mechanical connection between said main and auxiliary motors, a third hydraulic circuit including said third motor, a pump means forming a source of fluid under pressure and a hydraulically actuated start and stop valve, and governing means, including a fourth hydraulic circuit supplied with fluid from the pump of said third circuit and constituting a control circuit for said valves .and said reversing means, for determining the operation of said motors.

8. In a hydraulic power transmissionsystem, the combination of a main fluid motor, an auxiliary fluid motor, said motors being movable through forward and reverse strokes in the same direction, a third motor, a first hydraulic circuit including said main motor and a pump means forming a source of fluid under pressure for operating said main motor, a hydraulically actuated fluid flow reversing means determining the direction of fluid flow between the pump and said main motor, a second hydraulic circuit independent of said first circuit including said auxiliary motor, a pump means forming a source of fluid under pressure for operating said auxiliary motor and a hydraulically actuated reversing valve interposed between the pump and motor, means forming a separable mechanical connection between said main and auxiliaryr-motors, a

third hydraulic circuit including said third 'the combination of'a main fluid motor, an auxiliary fluid motor, said motors being movable through forward and reverse strokes in the same direction, a third motor, a first hydraulic circuit including said main motor and a pump means forming a source of fluid under pressure for operating said main motor, a hydraulically actuated fluid flow reversing means determining the directlon of fluid flow between the pump and said main motor, a second hydraulic circuit independent of said first circuit including said auxiliary motor, a pump means forming a source of fluid under pressure for operating said auxiliary motor and a hydraulically actuated reversing valve interposed between the pumpand motor, means forming a separable mechanical connection between said main and auxiliary motors, a third hydraulic circuit including said third motor, a pump means forming a source of fluid under pressure, a hydraulically actuated start and stop valve and a back pressure valve interposed between the start and stop valve and the pump of said third circuit, and governing means for said valves and said reversing means including a fourth hydraulic circuit connected to said third circuit intermediate the pump and the back pressure valve, electrically actuated valves in said fourth circuit governing the supply of control fluid to said reversing and start and stop valves and said reversing means, and an electrical control circuit for said electrical valves. I

10. In a hydraulic power transmission system, the combination of a main fluid motor, an auxiliary fluid motor, said motors being movable through forward and reverse strokes in the same direction, a third fluid motor, pump means forming a source of fluid under pressure for operating said motors, means for controlling the supply of fluid to said motors, means forming a separable mechanical connection between said main and auxiliary motors, and governing means for operating the control means to cause said main and auxiliary motors to move through a cycle of non-simultaneous but partially concurrent forward and reverse strokes with the main motor operating the auxiliary motor by said mechanical connection during the concurrent portion 01 said reverse strokes, and to retain the main and auxiliary motors at rest during reversal of strokes while the third motor moves through a cycle.

11. In a hydraulic power transmission system, the combination of a main fluid motor, an auxiliary fluid motor, said motors being movable through forward and reverse strokes in the same direction, a third fluid motor, pump means forming a'source of fluid under pressure for operating said motors, means for controlling the supply or fluid to said motors, means forming a separable mechanical connection between said main and auxiliary motors, and governing means for operating the control means to cause said main and auxiliary motors to move through a nonsimultaneous but partially concurrent forward stroke with the third fluid motor initiated and operated through a cycle upon the culmination of the forward stroke of said main and auxiliary motors and while said main and auxiliary motors are at rest; said main and auxiliary motors to move through a non-simultaneous but partially concurrent reverse stroke upon culmination of J the cycle of said third motor with the third motor again operating through a cycle upon culmination of the reverse strokes of said main and auxiliary motors, the main motor operating the auxiliary motor by said mechanical connection during the concurrent portion of said reverse stroke.

12. In a hydraulic power transmission system, the combination of a main fluid motor, an auxiliary fluid motor, said .motors being movable through forward and reverse strokes in the same direction, a third fluid motor, a flrst, a second and a third pump means forming a source of fluid under pressure for operating said main, said auxiliary, and said third motors respectively, means for controlling the supply of fluid to said motors including fluid flow reversing means for governing the supply of fluid to each said main and said auxiliary motors, and a start and stop valve means for governing the supply of fluid to said third motor, means forming a separable mechanical connection between said main and auxiliary motors, and governing means for operating the control means to cause said main and auxiliary motors to move through a cycle of nonsimultaneous but concurrent forward and reverse strokes, the main motor Operating the auxiliary motor by said mechanical connection during the concurrent portion of said reverse stroke, and with the main and auxiliary motors at rest during reversal while the third motor moves through a cycle.

13. In a hydraulic power transmission system,

the combination of a main fluid motor, an auxiliary fluid motor, said motors being movable through forward and reverse strokes in the same direction, a third fluid motor, 'a first, a second and a third pump means forming a source of fluid trol means including a control circuit and elec-- trically operated valve means in the control circuit governing the supply of control fluid to the valve and reversingmeans of said control means.

14. In a hydraulic power transmission system,

the combination of a main fluid motor, an auxiliary fluid motor, a work support indexing fluid ,7

motor, pump means forming a source of fluid under pressure for operating said motors, means for controlling the supply or fluid to said motors inclu'ding a hydraulically actuated fluid flow re versing means for each said main and said auxiliary motors, a pair of solenoid actuated valves for each of said reversing means and an electrical system including the solenoids of said solenoid actuated valves connected in parallel, and a switch device connected in series with said solenoids and opened by means driven by said index ing motor during the indexing operation thereof to prevent operation of either said main or said auxiliary motors.

15. In a hydraulic power transmission system, the combination of a main fluid motor, an auxiliary fluid motor, a work support indexing fluid motor, pump means forming a source of fluid under pressure for operating said motors, means for controlling the supply of fluid to said motors including a hydraulically actuated fluid flow reversing means for each said main and said auxiliary motors, and a hydraulically actuated start and stop valve for said indexing motor, a control fluid circuit including a pair of solenoid valves for each of said reversing means governing the supply of control fluid thereto and a single solenoid valve governing the supply of control fluid to said start and stop valve, and an electrical circuit for governing said solenoid valves to determine the operation of said motors including the solenoids of the solenoid valves, a pair of relays exercising control over said indexing motor, a first switch device actuated by means driven by said main motor at the end of operation thereof in a forward stroke to initiate operation of said indexing motor, and a second switch device actuated by means driven by said indexing motor operable after initiation of said indexing motor to establish a running circuit for said indexing motor independently of said first switch device.

JOHN W. PODESTA. 

